DE102019124145A1 - VEHICLE WHEEL AND METHOD OF MANUFACTURING THEREOF - Google Patents

Abstract

The invention relates to a stable one-piece wheel, which is particularly suitable for bicycles with an increased system weight, such as bicycles with electric drive or cargo bicycles, and a method for manufacturing the vehicle wheel. The vehicle wheel includes an annular portion 110, a plurality of spokes 120, and a hub portion 130, formed by injection molding a fiber-reinforced or carbon nanotube-containing thermoplastic in one piece, each of the plurality of spokes 120 having a substantially Z-shaped cross-section with a central leg 122 and a pair of outer legs 121, 123, the angle (γ) formed by each of the pair of outer legs and the central leg being greater than a right angle and the length of the central leg 122 from the annular portion 110 towards the hub portion 130 increases.

Description

Technical area

The present disclosure relates to the field of wheels for vehicle wheels and, more particularly, to an integral thermoplastic wheel and method of making the wheel. The wheel includes a plurality of spokes between a hub and an annular section and is particularly suitable for bicycles that are subjected to increased loads, such as bicycles with electric drive or cargo bicycles.

background

In view of the growing population in cities, there is a need for improved logistics systems in urban areas. From an environmental point of view, there is also a need to reduce carbon dioxide emissions and develop more sustainable transport solutions. One way to improve urban mobility is to offer shared use of bicycles, fleet bicycles, cargo bicycles, pedelecs or electric bicycles. In particular, when the vehicle wheels are configured to carry loads or to use electrical power generated by, for example, a motor and a battery, the loads on the system increase compared to conventional bicycles.

It is known that vehicle wheels, in particular for bicycles, should have a low weight. However, the forces that are exerted on a vehicle wheel can be very large. There is therefore a need for an affordable technical solution that provides sufficiently dimensionally stable and at the same time stable vehicle wheels, in particular bicycle wheels. Usually, material is added to improve material strength and thus the weight is increased.

In the case of bicycle wheels, spokes are commonly used to transfer forces between an annular rim portion and a hub. Typically, a higher number of spokes corresponds to a larger wheel thickness and a smaller number of spokes corresponds to a lighter wheel arrangement. However, a bicycle wheel with a smaller number of spokes must still be designed so that it can carry loads associated with the operation of the bicycle in order to avoid failure, especially at high speeds or large loads when electrically powered or load-bearing vehicles Bicycles are used.

An object of the present invention is to overcome the above-mentioned problems in the prior art and to provide a synthetic resin wheel excellent in mechanical properties while providing a product which is light in weight. Another object of the present invention is to provide a system that improves mechanical strength and flexibility in the event of overload peaks.

Other goals are to overcome the problem of relaxation and creep of thermoplastic material and to provide a safe and stable connection between the hub and another component such as an axle, an electric motor, a hub dynamo, a freewheel or a hub gear. Particularly in the case of a wheel for bicycles with electric drive, in which the motor is positioned in the hub of the wheel, it is also desirable to improve the heat dissipation or insulation of an electric motor.

Finally, in addition to the notable advantage of reduced weight and reinforcing structure, the possibility of mass production of the wheel should also be ensured. This property is beneficial in reducing costs and manufacturing fleet bicycles. The wheels should also be durable and easy to maintain.

Summary of the invention

The above objects are achieved by a vehicle wheel according to claim 1, which is particularly suitable for bicycles, electric bicycles and cargo bikes and which has an annular portion, a plurality of spokes and a hub portion formed from one piece, which is by injection molding of thermoplastic, which is fiber-reinforced or containing carbon nanotubes, wherein each of the plurality of spokes includes a substantially Z-shaped cross-section with a central leg and a pair of outer legs, the angle (γ), formed by each of the pair of outer legs and the central leg is greater than a right angle and wherein the length of the central leg increases from the annular portion to the hub portion. The present invention also provides a method of making the vehicle wheel. Other features and advantageous embodiments of the vehicle wheel and the manufacture thereof are set out in more detail in the dependent claims. The invention will be better understood from the following description and accompanying drawings.

A characteristic feature of the vehicle wheel is that each of the plurality of spokes includes a substantially Z-shaped cross-section with a central leg and a pair of outer or side legs, the angle (γ) made by each of the pair of outer legs and the middle Leg is formed is greater than a right angle and wherein the length of the central leg increases from the annular portion to the hub portion. The inclined Z-profile of each spoke enables the spokes to be constructed with low weight and contributes to the stability of the wheel.

The use of a Z-profile enables the length of the connecting line of the spoke to the annular section to be increased, along which forces are transmitted between the hub and the rim of the annular section. The rim is the part of the wheel on which a tire, such as a tubular tire or a clincher tire, is mounted. Furthermore, the increased width of the central leg of the Z-profile towards the hub increases the stability even further. In this way, the large vertical impact load, which is directed, for example, in the same direction as the longitudinal axis of a spoke, as is the case when driving over potholes, for example, can be withstood.

Depending on the material used and the desired stability, the weight of a 24-inch wheel is in the range from 900 g to 2000 g, preferably between 900 g or 1000 g and a maximum weight of 1250 g. The specified weight range is the weight of a reinforced thermoplastic without possible additional inserts such as a metal insert or the like.

In contrast to conventional metal bicycles with more than 30 spokes, the technical solution according to the present invention using reinforced thermoplastic significantly reduces the number of parts and components and enables great freedom of design. By using thermoplastic, design options such as color design can be improved and it is possible, for example, to add reflective materials to the material reinforced with carbon or glass fibers. The manufacture of vehicle wheels from thermoplastic materials such as polymers enables them to be cast in injection molds using an injection molding process, thereby providing an efficient manufacture of vehicle wheels that can be recycled.

According to a further aspect of the invention, the middle leg of the Z cross-section is angled with respect to the axis of rotation of the wheel (a).

According to a further aspect of the invention, each of the outer legs includes at least one curved portion that is directed towards the central leg.

By having one or more curved sections, the outer legs of two outer legs of adjacent spokes can be connected to one another at least partially sinusoidally on the hub portion and thus provide a seamless transition between the spokes. Furthermore, a curved portion can be provided at an intersection of an outer leg and the middle leg, thereby forming a rounded corner. This continuous joint reduces stress peaks such as notch stress during later use. Furthermore, the manufacture of the vehicle wheel using injection molding with injection tools is simplified, since sharp edges and undercuts are avoided.

According to a further aspect of the invention, the radius of the curved section increases towards the annular section. In this way, the curvature of the curved legs flattens so that the end sections of the flattened outer legs can approach the central axis of the annular section. As a result, the Z cross-section can provide not only high vertical stability, but also high lateral stability. When moving on a curved path or when colliding with moving or immobile objects from the side, e.g. in an accident, such side forces occur (see arrow 154 in 3b) usually in the vicinity of the annular section or at the edge of the rim.

Simulation results showed that the safety requirements for bicycles according to standardized norms such as DIN EN ISO 4210.6: 2012-11 with a side load of 370 N can be met with the vehicle wheel and the geometric structure of the spokes of the present invention. Furthermore, the results of the simulation at a temperature of 80 ° C showed that bicycles with suspension on both sides can absorb vertical impact loads of up to 4000 N. The wheel according to the invention therefore meets the high safety requirements

According to another aspect of the invention, the curved sections of the outer legs have a radius (r1) in a range between 3 and 20 mm and each z-shaped cross section has a wall thickness (S) in a range between 1.5 and 5 mm, preferably between 2.5 and 3 mm.

The above excellent stability properties in the vertical and lateral direction, which also include the absorption of torques generated by braking or accelerating the bicycle, can be achieved by the above-mentioned relatively small wall thickness ranges of the spokes can be achieved.

According to another aspect of the invention, the length of the outer legs increases continuously towards the area for connection to the annular section in order to widen the line along which the Z-profile is connected to the annular section. In this way, the stability of the wheel can be increased even further.

According to another aspect of the invention, the z-shaped cross section of each spoke is configured to be torsionally resilient to compensate for a load directed substantially vertically to the outer periphery of the annular portion in a section between two adjacent spokes.

One of the critical points in operating a wheel with a below normal number of spokes and experiencing vertical impact loads is the fact that there are portions of the annular section where no spokes are connected and therefore that in there are local peak loads in this area. This problem is addressed by the present invention by means of the Z-shaped spokes which are configured to respond elastically when forces are directed vertically with respect to a spoke-less section of the annular section. In other words, the vehicle wheel according to the invention is based on the elastic bending of components, i.e. H. each outer leg of a pair of adjacent Z-shaped spokes, so that the energy exerted by the vertical impact loads on the spoke-less sections of the annular section can be efficiently dissipated.

In accordance with another aspect of the invention, the outer legs of each Z cross-section are configured to allow deflection in the direction of a curve.

In the case of a vertical impact between two spokes, when the force is exerted at the same distance from each of the adjacent spokes, the facing outer legs bend like a torsion bar spring and distribute the load of the vertical impact evenly on both spokes.

In another aspect of the invention, the wheel includes at least four spokes and the ends of the legs of each spoke are joined at the hub to form semicircular or at least partially elliptical windows defined between the annular portion and pairs of adjacent spokes.

The wheel includes at least four spokes, preferably 6 spokes. In this way, the geometric structure of the window between two spokes is semicircular or at least partially elliptical, so that notch stress can be avoided. Particularly in the case in which the geometric structure of the hub section is configured to accommodate larger components such as an electric motor, the windows are essentially elliptical with a longitudinal axis that runs parallel to a tangent through the corner point on the annular section .

According to another aspect of the invention, the hub section includes a metal insert or a plastic insert, which is connected by injection molding or by using residual heat of the hub section produced by means of injection molding and is configured to accommodate at least one of an axle, an electric motor, a hub dynamo, a hub gear to hold a freewheel or a wheel bearing, whereby the wheel suspension can be configured on one or both sides.

In this way, the vehicle wheel can be securely connected to various components. It should be noted that the vehicle wheel with an insert is nevertheless light in weight. In the case of a wheel for a 24 inch tire, the weight of a wheel with a metal insert is in the range between 1200 g and 1450 g. Steel, for example, can be used as the metal.

According to another aspect of the invention, the metal insert contains openings for an injection-molded and form-fitting connection.

In this way the connection of the metal insert is improved. These openings can have various shapes, such as a teardrop shape. According to another aspect of the invention, the hub portion is pseudo-pentagonal or pseudo-hexagonal shaped with rounded corners and has on one side a radially inwardly directed edge or a radially inwardly directed flange for mounting an electric motor, each of the corners having a vertically extending pair of ribs for guiding the connecting elements and for forming an air gap when the electric motor is mounted.

By providing an air gap, insulation is provided against the heat that may be generated by the mounted electric motor.

According to another aspect of the invention, the fiber-reinforced thermoplastic has a glass fiber content of 20 to 65% by weight and the Thermoplastic is selected from PA6, PA6.6 or a mixture thereof.

These polymers and mixtures of PA6 and PA6.6 show good flow behavior and are easy to process, so that they can be applied well to stressed functional parts such as vehicle wheels. The material of the manufactured wheel is stable in a temperature range from -20 ° C to 80 ° C. The inventors have made investigations on this and found out in experiments that in particular a mixture of PA6 and PA6.6, which contains 30% glass fibers, is suitable for the vehicle wheel. Suitable glass fiber reinforced thermoplastics are commercially available, for example under the trade name Grivory® from EMS-Grivory, EMS Chemie AG, Switzerland.

Simulations of the behavior of the vehicle wheel with a mixture of PA6 and PA6.6 with 30% glass fiber, as provided by EMS-Grivory® under the name Grilon TSG-30 (TS = PA66 + PA6; G = glass fiber reinforced), showed that also with With a material temperature of 80 ° C and assumed exerted forces that include a vertical impact of 4000 N, a braking torque of 305 N and a side load of 370 N according to EN ISO 4210-6: 2012-11, no permanent deformation of the material occurred . Any noticeable slight deformation of the wheel occurred within the elastic limit of the material.

According to another aspect of the invention, a preferred glass fiber reinforced or carbon nanotube-containing thermoplastic has a tensile stress at break of 100 MPa to 300 MPa and a modulus of elasticity of at least 6000 MPa to 30 GPa, preferably 15 GPa to 25 GPa. The tensile strength and the modulus of elasticity correspond to the European standard EN ISO 527 .

According to another aspect of the invention, the annular portion includes a rim with a symmetrical profile having two diverging legs directed radially outward, each end portion having a one-piece rim flange which extends inwardly towards the axis of symmetry of the profile extends, has.

Based on this rim construction, the rim forms an open hollow profile in the outward radial direction which can be configured as a V-shaped, U-shaped, trapezoidal or curved shape with a plurality of curved sections on each leg. Clincher tires can be held by means of the protruding rim flange. These tires have a bead of wire or aramid fiber that is locked with flanges in the rims.

According to another aspect of the invention there is provided a method of manufacturing a vehicle wheel, the method including the steps of: injection molding a fiber-reinforced or carbon nanotube-containing thermoplastic to form a one-piece body that includes an annular portion, a plurality of spokes and a hub portion one piece, the plurality of spokes forming a substantially Z-shaped cross-section with a central leg and a pair of outer legs, the angle (γ) formed by each of the pair of outer legs and the central leg being greater than is a right angle; and
wherein the length of the central leg increases from the annular portion to the hub portion.

According to another aspect of the invention, the method further includes the following: connecting an insert made of metal or plastic to the hub portion by injection molding through the openings of the inlet and overmolding at least part of the insert in a force-fitting and / or form-fitting manner.

In this way the insert can be fixed immovably on the hub portion.

According to another aspect of the invention, the method further includes: providing and extracting a plurality of radially disposed vanes with a pleat core in the injection tool to form an annular portion including a rim with a symmetrical profile having two radially outwardly directed having diverging legs, each end portion having an integral rim flange extending inwardly.

Another advantage of the manufacturing method for wheels according to the invention is the fact that the manufacturing can be scaled to all conventional dimensions and rim dimensions for bicycles and cargo bikes, for example given by the ETRTO (European tire and rim expert organization). Preferred nominal wheel diameters are those suitable for tire dimensions of 16 to 28 inches, more preferably 18 to 26 inches, even more preferably 20 to 26 inches, and most preferably 20 to 24 inches. The rim width (width of the hollow profile) is preferably 14 to 35 mm, more preferably 25 to 32 mm. In the case of clincher tires, the outer tire width is preferably 2.3 inches and can for example, can be combined with an outer tire diameter of 24 inches.

Figure list

• 1a zeigt eine Draufsicht des Fahrzeugrades gemäß einer Ausführungsform der vorliegenden Erfindung;
• 1b zeigt eine Schnittansicht einer Speiche des Fahrzeugrades;
• 1c zeigt schematisch eine einzelne Speiche;
• 2a zeigt eine andere Ansicht des Fahrzeugrades;
• 2b zeigt einen Ausschnitt aus 2a;
• 2c zeigt vier Querschnitte der Speiche, wie in 2a angegeben;
• 2d zeigt Einzelheiten von zwei Querschnitten der Speiche;
• 3a zeigt einen zu der Radscheibe vertikal verlaufenden Schnitt entlang einer Speiche;
• 3b zeigt auf das Rad ausgeübte Kräfte schematisch;
• 4a zeigt eine zwischen zwei Speichen ausgeübte vertikale Kraft schematisch;
• 4b zeigt die Torsion eines z-förmigen Querschnitts der Speiche schematisch;
• 5a zeigt die Herstellung des ringförmigen Abschnitts schematisch;
• 5b zeigt zwei Querschnitte des ringförmigen Abschnitts, der in 5a gezeigt ist;
• 5c zeigt einen ringförmigen Abschnitt, wobei ein Reifen in das Hohlprofil der Felge eingesetzt ist;
• 6a bis 6c zeigen eine Draufsicht auf das Hohlprofil der Felge und detaillierte Ansichten des Ventilanschlussstücks;
• 7 zeigt eine Achse mit Gehäuse, die in den Nabenabschnitt eingesetzt werden soll, schematisch;
• 8 zeigt eine perspektivische Ansicht des Fahrzeugrades;
• 9a bis 9d zeigen Querschnitte und Einzelheiten des Fahrzeugrades und des Nabenabschnitts, einschließlich eines Einsatzes;
• 10a und 10b zeigen eine Draufsicht und eine Seitenansicht des Einsatzes;
• 11a und 11b zeigen eine schematische perspektivische Ansicht und eine Explosionsansicht;
• 12a bis 12c zeigen Querschnitte des Nabenabschnitts;
• 13a und 13b zeigen aerodynamische Ströme eines sich drehenden Rades schematisch; und
• 14a bis 14c zeigen einseitige und beidseitige Aufhängungen.

The accompanying figures illustrate exemplary embodiments of the disclosure and serve to explain the principles of the disclosure on the basis of examples and it is not intended that these are drawn to scale. The figures are included to provide an illustration and better understanding of the various aspects and embodiments, but are not intended to limit the disclosure to the embodiment illustrated in the figures or to be drawn to scale. Where technical features in the figures or the detailed description are followed by reference symbols, the reference symbols have been included solely for the purpose of improving the intelligibility of the figures and the description. For the sake of clarity, each component may not have been labeled in each figure.

• 1a Fig. 10 shows a top view of the vehicle wheel according to an embodiment of the present invention;
• 1b shows a sectional view of a spoke of the vehicle wheel;
• 1c shows schematically a single spoke;
• 2a Figure 11 shows another view of the vehicle wheel;
• 2 B shows an excerpt from 2a ;
• 2c shows four cross sections of the spoke as in 2a specified;
• 2d shows details of two cross sections of the spoke;
• 3a shows a section along a spoke running vertically to the wheel disc;
• 3b shows schematically forces exerted on the wheel;
• 4a shows schematically a vertical force exerted between two spokes;
• 4b shows the torsion of a z-shaped cross section of the spoke schematically;
• 5a shows the production of the annular section schematically;
• 5b FIG. 11 shows two cross sections of the annular portion shown in FIG 5a is shown;
• 5c shows an annular section with a tire inserted into the hollow profile of the rim;
• 6a to 6c show a top view of the hollow profile of the rim and detailed views of the valve connector;
• 7th shows a shaft with housing to be inserted into the hub portion, schematically;
• 8th Figure 3 shows a perspective view of the vehicle wheel;
• 9a to 9d show cross-sections and details of the vehicle wheel and hub portion including an insert;
• 10a and 10b show a plan view and a side view of the insert;
• 11a and 11b show a schematic perspective view and an exploded view;
• 12a to 12c show cross sections of the hub portion;
• 13a and 13b show aerodynamic flows of a rotating wheel schematically; and
• 14a to 14c show unilateral and bilateral suspensions.

Detailed description of the figures

• den ringförmigem Abschnitt 110, eine Vielzahl von Speichen 120 und den Nabenabschnitt 130.

1 Figure 3 shows a top view of a vehicle wheel 100 according to an embodiment of the present invention. The vehicle wheel consists of only one piece, which can be divided into three main sections:

• the annular section 110 , a variety of spokes 120 and the hub portion 130 .

In the 1a The shown view of the vehicle wheel illustrates the side with the hub portion 130 is configured about an axis (not shown) and optionally other components 160 such as an electric motor, a hub dynamo, a gear hub, a freewheel or a wheel bearing. Accordingly, the vehicle can be used for certain purposes, for example for bicycles in which an electric motor is positioned in the center of the wheel, as well as for load-bearing two or three-wheelers.

A characteristic feature of the vehicle wheel is that each of the plurality of spokes has a substantially Z-shaped cross section with a central leg 122 and a pair of outer legs 121 and 123 includes. Furthermore, the width of the middle leg increases 122 from the annular portion to the hub portion 130 towards. Therefore, the spoke tapers towards the annular section or the rim. This geometric structure is made possible by the curved dot-dash lines in 1b Figure 3 illustrates a sectional view of a spoke 120 of the vehicle wheel 100 shows. Furthermore, the white dot-dash line in 1c the enlarged cross-section created by the Z-profile of the spoke 120 is implemented and which enables the spoke to take large loads off the rim 110 to the hub 130 and vice versa. 2a FIG. 13 shows a representation of the opposite side with respect to that in FIG 1a Shown view of the vehicle wheel 100 . Every pair of adjacent spokes 125 , 126 and the respective sub-section of the annular section 110 which extends between the intersections of each spoke with the rim (see reference numbers 128 and 116 ), defines a window 140 . The window essentially forms an ellipse with length b3 and width h3, as in FIG 2 B shown. This window 140 also forms a substantially semicircular section, which is indicated with radius r3 and through the outer side legs 123 , 121 of the pair of adjacent spokes 125 , 126 is defined. The outer thighs 123 , 121 are near the hub section 130 connected with each other.

In the 2a The embodiment shown has 6 spokes and a pseudo-hexagonal hub portion 130 with a radius 131 that is off the axis of rotation 137 of the vehicle wheel to the outer edge of the rounded corner 132 of the pseudohexagon extends on. Accordingly, the spokes are preferably equidistant from adjacent spokes. Alternative designs with 3 to 5 spokes are also possible. The geometric structure of the hub section 130 is configured to accommodate larger components than an electric motor. Based on this geometric structure of the hub section 130 is the ellipse of the window 140 substantially elliptical, having a longitudinal axis that is parallel to a tangent through the corner point on the annular section 130 runs.

Furthermore there 2a by broken lines 4 sections AA, BB, CC and DD of the spoke 125 which can be, for example, 30 mm apart. These cross-sections are in 2c respectively 2d shown. They show that all four z-shaped cross-sections are point-symmetrical, with the center of symmetry P at the intersection of the vertical axis (dashed line) and the longitudinal axis of the middle leg 122 lies.

The dashed line of each cross section is parallel to the axis of rotation of the wheel. That is, the middle leg 122 is angled with respect to the axis of rotation of the vehicle wheel (a). Compared to the center plane of the wheel disc, this obliquely angled Z-profile forms a flatter spoke than a Z-profile with a central leg that is parallel to the axis of rotation 137 extends and is vertical to the center plane of the wheel disc. In this context, “wheel disc” refers to the part of a wheel that contains a carrier element between the axle or the hub section and the rim. The flattening of the z-shaped cross-section by inclining the middle leg 122 as well as the curvature of the outer legs 121 , 123 to the middle thigh 122 Hin is particularly advantageous on the connecting line of the annular section, which has only a limited width.

Each of the outer thighs 121 , 123 includes at least one curved section leading to the middle leg 122 is directed towards, where the radius (r1, see also 2d ) of the curved portion increases towards the annular portion. The curved sections preferably have a radius (r1) in a range between 3 and 20 mm. In addition, the transition from the outer or side legs to the middle legs is rounded in order to reduce the notch stress.

Sections CC and BB represent the middle section of the spoke 120 dar and their Z-profiles have shorter lengths than those of the sections AA and DD. Furthermore, the length of the middle leg increases from the annular section to the hub section (from section DD to AA).

2d Figure 12 shows details of sections AA and DD which are close to the hub portion and the annular portion, respectively. The angle (γ) made by each of the pair of outer legs 121 , 123 and the middle thigh 122 is enclosed is larger than a right angle,
wherein the length of the central leg increases from the annular portion to the hub portion.

2d also gives the thickness S of the wall of the middle leg 122 at. The thickness of each leg is constant along the spoke. As can be seen, the Z-profiles form solid spokes and are not formed as hollow spokes. Accordingly, weight can be saved by providing relatively thin walls. Each z-shaped cross section preferably has a wall thickness S in the range between 1.5 and 5 mm, preferably between 2.5 and 3 mm.

2d shows in section DD, which is close to the annular section 110 the dimension t1, which is parallel to the width of the rim, and the dimension b1 of each outer leg at section DD, which is parallel to the longitudinal axis of the rim. While t1 is significantly longer in the section AA close to the hub, b1 is close to the hub section 130 shorter than b1 close to the annular portion 110 . Along the outer periphery of the hub portion 130 form the outer legs 121 , 123 of the spokes 120 an at least partially sinusoidal connecting line 136 because each outer leg of one spoke is connected to the leg of the adjacent spoke. This creates a seamless transition between the spokes 120 ready, wherein the wave-like shape is limited to the portion between the adjacent middle legs.

3a shows another cross-section of a spoke, which runs vertically to the wheel disc plane and along a spoke, this having a height h1. 3a shows a partially sinusoidal connecting line at the connection point with the hub section 136 between the outer thigh 123 the illustrated spoke and an adjacent spoke (not shown). The width of the spoke t1 is illustrated and shows the maximum extent t1max at the hub portion 130 and the minimum extent t1min close to the bottom 113 of the annular section 110 , the transition between t1max and t1min being continuous and in a tapered spoke 120 with a concave outline of radius r2 (not shown in full length).

The width t1 is less than the width t3 of the hub portion. The width t1 is less than the maximum width of the rim of the annular section. The annular section 110 forms a rim with an open hollow profile in the outward radial direction that has a modified V-shape with curved shapes on each of the legs 111 and 112 and with curved sections on each leg. Also give the arrows 156 and 157 suggest that the spoke can be twisted when there is a vertical force between the two adjacent spokes 152 exercised as in 3b with arrow 152 specified.

3b shows other forces such as the vertical force (arrow 151 ) exerted on the longitudinal axis of a spoke and the lateral forces 154 . When moving on a curved path or in the event of a collision in an accident, lateral forces (see arrow 154 in 3b) exerted near the annular portion or at the edge of the rim.

Further torques can be exerted on the wheel. When the wheel is accelerated or rotated, a force occurs along the circumference of the rim 153 that includes one of a starting torque, a driving torque, or an acceleration torque. By means of a device for braking such as the disc brake 135 can further opposite torques in the direction of the arrow 155 occur.

4a and 4b show the case in more detail in which in a section between two adjacent spokes 125 and 126 a vertical force F (see arrow 152 ) is directed substantially vertically to the outer periphery of the annular portion. The dashed ellipse 142 and corresponding arrows illustrate the elasticity response of the outer leg 123 (from spoke 125 ) and the outer leg 121 (from spoke 126 ) facing each other and the window 140 at least partially surrounded. 4b illustrates schematically the elastic torque of the spoke 126 , with the upper side thigh 121 Twisted upwards in relation to the wheel disc plane (see dash-dot line 129 ).

The exerted energy (F, 152) can be effectively dissipated by bending and twisting the spoke elements involved. That is, the outer legs of each Z cross-section are configured to allow bending in the direction of curvature to absorb the large loads. As a result, each of the facing outer legs bends like a torsion bar and distributes the load of the vertical impact evenly on both spokes. It is known that the bending stress σ _b (torque M / work W) of a leaf spring with height h, length I and width b can be calculated as follows: $${\mathrm{\sigma }}_{\text{b}}=\text{M / W}=\left(\mathrm{6th}\ast \text{F.}\ast \text{I.}\right)\text{/}\left(\text{b}\ast {\text{H}}^2\right)$$

Such general formulas and formulas derived therefrom can be used to _{estimate the maximum permissible stress σ bmax} , the length I of the spring corresponding to the length of the bending element of the Z-profile analogously to a torsion bar spring.

5b shows the manufacture of the annular section 110 schematic. 5a illustrates that the annular section is a hollow profile with two diverging legs 111 and 112 which are directed radially outward, the profile being symmetrical. Each end portion of the diverging legs 111 , 112 has a one-piece rim flange 114 which extends inwardly towards the axis of symmetry of the profile. By means of the protruding rim flange 114 can for example be a clincher 119 be held (see 5c ).

Furthermore, the hollow profile comprises transverse ribs 115 , which divide the hollow profile into a large number of sub-areas. The annular section of the vehicle wheel in 5a is in 12 Subareas divided (see dashed arched sub-sections), with each subarea having a plurality of ribs 115 that have the same orientation as the radially outwardly directed axis in the center of each sub-region.

Around this complex structure with ribs 115 and rim flange 114 it is necessary to use radially arranged slides (see arrows 118 ) to be used with a folding core.

6a-6c show a top view of a hollow profile with a plurality of ribs 115 and detailed views of a valve connector 117 . The valve connector 117 is configured to fit into 3 adjacent chambers formed by the rib structure. The bottom shape of the valve connector 117 is configured to fit in two chambers with a chamber between them. The middle chamber in between has a through-hole on its underside so that a valve can be inserted.

7th shows a schematic sectional view of a component 160 that are to be inserted into the housing of a rear or front hub and contain at least one axle and optionally a freewheel mechanism, a gear shift, a wheel hub motor or a surrounding housing. As an alternative to the embodiment shown, a hub motor, a gearshift or other component that can be used by the hub portion 130 can be included, at least partially used without a housing when the hub portion 130 has been configured to serve at least in part as a housing for the mountable component. The electric wheel hub motor 160 , which preferably drives a rear wheel hub, has an assembly width E of, for example, about 140 mm.

Furthermore, the reference symbol F shows the extent of a plug-in axle diameter (front / rear). The diameters of front thru axles can range between 9 and 20 mm and preferably comprise 10 mm, 12 mm or 15 mm. Rear axles typically have a diameter of 10 or 12 mm. Thru axles are known, for example, from mountain bikes. The thru-axle can also be combined with a bicycle with disc brake and is not only suitable for mountain bikes, but also for road bikes and bikes with electric drive.

8th Figure 13 shows a perspective view of the vehicle wheel and the hub portion 130 from the side including a cavity configured to accommodate a wheel hub electric motor 160 to record. The hub section is pseudo-hexagonal, with the widest inner diameter being D _HUB . In each of the rounded corners of the pseudo-hexagon are a pair of ribs 134 provided. Ribs 134 can reinforce the hub shell and can be used to secure the fasteners such as screws (see reference number 161 in 11a or 12a) for fastening the electric motor in the hub section 130 respectively.

9a to 9d show cross sections of the vehicle wheel and the hub portion 130 including an operation 139 and the sectional views MM and NN. The use 139 is in the hub section 130 and in particular on a flange 133 extending from the pseudo-hexagonal hub section 130 of the wheel extending radially inward, attached. The metal insert is used to hold assemblable components that contain at least one wheel axle. In the present exemplary embodiment, the wall of the hub portion extends 130 parallel to the axis of rotation (dashed-dotted line) and is in contact with the insert 139 (please refer 9b) .

A side view and a top view of a metal insert 139 are in 10a and 10b shown. The metal insert 139 points for better anchoring of the insert 139 on the flange 133 openings 138 on each side of the rounded corner 132 of the pseudo hexagon. The openings are tapered in the direction away from the screw hole 166 and essentially form a teardrop shape. The use 139 is with the hub section 130 by injection molding through the openings 138 (see shaded area in the openings 138 in section MM) and back injection (see reference number 163 and shaded area in section NN) of at least part of the insert 139 connected in order to obtain frictional and positive locking.

11a and 11b Figure 12 shows a schematic perspective view and an exploded view of a plurality of wheel components. There are fasteners such as screws 161 provided to a disc brake 135 to fix. More screws 161 are provided to the deployable component 160 that includes an in-wheel electric motor.

With respect to the annular section 110 of the wheel shows 11a a rim tape 165 which is particularly useful when clincher tires are attached to the rim. The rim tape preferably rests on the transverse ribs 115 of the hollow profile and supports the inner tube (not shown) against the tire pressure. A valve connector is used to inflate a tire 117 provided (see also 6b and 6c ).

11b shows the vehicle wheel in the assembled state, with the rim tape 165 and the valve connector 117 into the hollow profile of the annular section 110 or the rim are inserted. In the hub section 130 becomes a component 160 , which includes an axle and an electric in-wheel motor, is used, the disc brake 135 on the other side of the wheel.

12a to 12c show cross sections of the hub portion 130 in the mounted or assembled state of the vehicle wheel 100 . In each of the rounded corners 132 (please refer 12c ) can use screws or other fasteners 161 be introduced to provide a solid connection between the component 160 and the hub portion 130 to build. By turning the screws axially 161 through the holes 166 of the insert and the corresponding holes of the hub section 130 can any screw 161 against the metal insert 139 be pressed. As a result, the axial screw preload can be maintained permanently. It is particularly advantageous that the disadvantages of the thermoplastic material such as relaxation and creep by bonding with a metal insert 139 can be prevented and a safe, stable and stable connection between the hub and another component such as an axle, an electric motor, a hub dynamo or a hub gear can be provided.

Further, reinforce the construction of the inner hub portion 130 and especially the use of the ribs 134 not only the hub housing, but can do the foregoing opposites 127 the component that can be used 160 also lead into the assembled position. Furthermore, the ribs allow 134 that between the rounded corners 132 of the pseudo-hexagonal hub section (see section BB) an air gap 164 between the outer case of the component 160 and the inner wall of the hub portion 130 provided. This is especially beneficial when the component 160 includes a heat source such as an electric motor so that this volume of air can act as insulation.

13a and 13b show the aerodynamic flows of the operating vehicle wheel schematically. A rotary movement of the vehicle wheel is indicated by an arrow 167 specified. When the wheel turns with its z-shaped spokes, there are air currents 168 triggered. For example, air currents run 168 past the heated brake disc or the heated electric motor. Therefore, the heat that may be produced by a heat source such as a hub motor in the center of the wheel can be effectively reduced by moving the air away from the source.

13b shows by means of dashed arrows the air flows in the case of a rotating wheel (see direction of rotation about the axis indicated by arrow 149 is indicated) along the z-shaped cross-section of an exemplary spoke 120 . In this way can heat radiation 169 (indicated by the white arrow) of a heat source such as an electric motor can be carried away from the source.

14a to 14c show the one-sided suspensions 171 and 172 as well as a double-sided suspension 170 . Suspensions on both sides as in 14a shown, make it possible to use the bike on a two-wheeler, for example. When the double-sided suspension 170 with the one-sided suspensions of 14b and 14c combined, a tricycle can be formed. Furthermore, single-sided suspensions make it possible, for example, to provide vehicles with four-wheel drive, in which a hub motor can optionally be provided in one, two or each wheel hub. Accordingly, the wheel according to the invention can be combined with a large number of vehicles. Such vehicles, which use wheels according to the invention, can be driven by central motors or hub motors, as required.

In summary, the vehicle wheel according to the invention has excellent stability properties and can be used in a wide range of applications, including cargo bicycles and electrically operated bicycles such as pedelecs or electric bicycles. Since the wheel according to the invention meets high safety requirements, the bicycles can be used as road bicycles. In particular, the wheel is suitable for use for fleet bicycles, since it can be produced quickly and in large quantities in one process step and maintenance in operation is simple.

List of reference symbols

100

Vehicle wheel

110

annular section

111

Legs of the hollow profile of the rim

112

Leg 111 facing leg

113

Underside of the hollow profile of the annular section

114

inward protruding rim flange

115

rib

116

Intersection of spoke 126 with the rim

117

Valve connector

118

Slider

119

Clincher tires

120

spoke

121

outer thigh

122

middle thigh

123

opposite outer leg

125

another spoke

126

adjacent spoke

127

protruding element for the ribs 134

128

Point of intersection of the spoke 125 with the rim

129

Plane along the center of the wheel disc

130

Hub section

131

Maximum radius of the pseudo hexagon

132

rounded corner

133

flange

134

Pair of ribs

135

Disc brake

136

partially sinusoidal connecting line between spoke and hub section

137

Axis of rotation

138

openings

139

Metal insert

140

Window in the wheel disc

142

ellipse

143

Holes in flange 133

149

Axis of rotation

151

vertical force exerted on the spoke axis

152

vertical force exerted between the spokes

153

Starting torque, drive torque and acceleration torque

154

Lateral force

155

Braking torque

156

Twisting of an outer leg

157

Twisting of an opposite outer leg

160

usable component such. B. an electric motor with an axis

161

screw

163

Perimeter portion that is partially molded around insert 139

164

Air gap

165

Rim tape

166

Holes of the insert

167

Rotary motion

168

Air currents

169

Heat radiation

170

suspension on both sides

171

one-sided suspension on the right

172

one-sided suspension on the left

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Non-patent literature cited

• DIN EN ISO 4210.6: 2012-11 [0017]
• EN ISO 527 [0035]

Claims (18)

A vehicle wheel that includes: an annular portion (110), a plurality of spokes (120), and a hub portion (130) formed by injection molding a fiber-reinforced thermoplastic or a thermoplastic containing carbon nanotubes in one piece, wherein each of the plurality of spokes (120) includes a substantially Z-shaped cross-section with a central leg (122) and a pair of outer legs (121, 123), the angle (γ) made by each of the pair of outer legs ( 121, 123) and the middle leg (122) is larger than a right angle; and wherein the length of the central leg increases from the annular portion to the hub portion. Vehicle wheel according to Claim 1 , the middle leg being angled (a) with respect to the axis of rotation of the wheel. Vehicle wheel according to Claim 1 or 2 wherein each of the outer legs (121, 123) includes at least one curved portion directed toward the central leg (122). Vehicle wheel according to Claim 3 wherein the radius (r1) of the curved portion increases towards the annular portion. Vehicle wheel according to Claim 3 or 4th , wherein the curved sections have a radius (r1) in a range between 3 and 20 mm and each z-shaped cross section has a wall thickness (S) in a range between 1.5 and 5 mm, preferably between 2.5 and 3 mm, having. Vehicle wheel according to one of the preceding claims, wherein the length of the outer legs (121, 123) increases continuously towards the area for connection with the annular section, around the line along which the Z-profile is connected to the annular section (110 ), to expand. A vehicle wheel according to any preceding claim, wherein the z-shaped cross-section of each spoke (120) is configured to be torsionally resilient to compensate for a load that is substantially vertical to the outer periphery of the annular section in a section between two adjacent ones Spokes (125, 126) is directed. Vehicle wheel according to one of the Claims 3 to 7th wherein the outer legs (121, 123) of each Z-section are configured to allow deflection in the direction of a curve. Vehicle wheel according to one of the preceding claims, wherein the wheel includes at least four spokes (120) and the ends of the legs of each spoke (120) are connected at the hub to form semicircular or at least partially elliptical windows (140) formed between the annular section ( 110) and pairs of adjacent spokes (125, 126) are defined. Vehicle wheel according to one of the preceding claims, wherein the hub section (130) includes a metal insert or a plastic insert, which is connected by injection molding or by using residual heat of the hub section produced by means of injection molding, configured to rotate around at least one of an axle, an electric motor (160 ), a hub dynamo, a hub gear or a wheel bearing, whereby the wheel suspension can be configured on one or both sides. Vehicle wheel according to Claim 10 , wherein the metal insert contains openings (138) for an injection-molded connection with a form fit. Vehicle wheel according to Claim 11 wherein the hub portion (130) is pseudo-pentagonal or pseudo-hexagonal with rounded corners (132) and has on one side a radially inwardly directed edge for mounting an electric motor, each of the corners having a vertically extending pair of ribs for guiding the connecting elements and the Forming an air gap when the electric motor is mounted includes. Vehicle wheel according to one of the preceding claims, wherein the fiber-reinforced thermoplastic has a glass fiber content of 20 to 65% by weight; and wherein the thermoplastic is selected from PA6, PA6.6 or a mixture thereof. Vehicle wheel according to Claim 13 , wherein the glass fiber reinforced or carbon nanotube-containing thermoplastic has a tensile stress at break of 100 MPa to 300 MPa and a modulus of elasticity of at least 6000 MPa. A wheel according to any one of the preceding claims, wherein the annular portion includes a rim with a symmetrical profile having two diverging legs directed radially outward, each end portion having a one-piece rim flange which extends inwardly toward the axis of symmetry of the Profile extends out, having. A method of manufacturing a vehicle wheel, the method comprising the steps of: injection molding a fiber reinforced or carbon nanotube-containing thermoplastic to form a one-piece body including an annular portion, a plurality of spokes and a hub portion, the plurality spokes form a substantially Z-shaped cross-section with a central leg and a pair of outer legs, the angle (γ) formed by each of the pair of outer legs and the central leg being greater than a right angle; and wherein the length of the central leg increases from the annular portion to the hub portion. Procedure according to Claim 16 which further includes: connecting an insert made of metal or plastic to the hub portion by injection molding through the openings of the inlet and overmolding at least a part of the insert in a force-fitting and / or form-fitting manner. Procedure according to Claim 16 or 17th further comprising: providing and extracting a plurality of radially disposed vanes having a pleat core in the injection tool to form an annular portion including a rim having a symmetrical profile having two radially outwardly directed diverging legs, each End portion has a one-piece rim flange (114) extending inwardly.

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